eLFH - Heat and Temperature Flashcards
Temperature dependent enzymatic reactions mechanism
Increase in temperature leads to reacting molecules gaining kinetic energy
Increases likelihood of collision between enzyme and substrate
Thus increases rate of reaction
Explanation for there being an optimal temperature for temperature dependent enzymatic reactions
There is a temperature at which an enzyme’s catalytic activity is greatest
Above that temperature, enzyme structure begins to denature
Optimal temperature for temperature dependent enzymatic reactions
+ exception to this
37.0 degrees Celsius
Except enzymes in testes which function optimally at slightly lower temperature
Energy definition
Ability to do work
Can be mechanical, chemical, electrical or thermal
Heat (or heat energy) definition
Total energy of molecular motion in a substance
Cannot be directly measured
Heat equation
Equation for Kinetic energy
Kinetic energy = 1/2 Mass x Velocity^2
Factors which Heat / Heat energy depends on
Kinetic energy of molecules of a substance
Physical state of the substance
Number of molecules in the substance (i.e its mass)
Temperature definition
Average kinetic energy of atoms which make up a substance
When temp is measured in Kelvin, it is directly proportional to average kinetic energy of molecules in the substance
Relationship between heat energy and temperature
Temperature is measure of likelihood that one substance will transfer heat energy to another
Eg. Iceberg has higher amount of heat energy than pan of boiling water (due to its mass) but boiling water is higher temperature and would transfer heat energy to iceberg
Specific heat capacity definition
Amount of heat energy required to raise temperature of 1 kg (a unit mass) of a substance by 1 Kelvin (a unit temperature rise)
Specific heat capacity Equation
Units of specific heat capacity
kJ / kg / K
can also be as kcal / kg / K
Conversion of kJ to kcal
1 kcal = 4.18 kJ
Heat capacity definition
Amount of heat energy required to raise the temperature of a given OBJECT by 1 Kelvin
I.e Heat capacity = Specific heat capacity x Mass of object
Units of heat capacity
kJ / K